The environment of ages past has shaped who we are today, even (or especially) the difficult, unpleasant stuff – this is the foundation of ancestral health. Take exercise. Early man’s daily life was one of frequent, constant activity interspersed with infrequent bouts of intense activity. Hard exercise is, well, hard and physically unpleasant in the moment, and constant low level activity is often untenable given modern schedules, but both make us stronger, healthier, and ultimately happier. Intermittent fasting, while difficult, can be beneficial when artificially imposed today because our genome evolved under periods of nutritional stress where food was scarce. Going without food from time to time was expected; it was our genome’s evolutionary backdrop. Our bodies evolved with these hardships as assumed and inevitable aspects of the environment. Our modern bodies function best when exposed to these hardships.

What about another almost unavoidable aspect of the ancestral environment – parasites? Do our bodies expect and function best with a few (dozen) worms along for the ride? You know about gut flora’s effect on our immune response and overall health, but does the fact that our immune systems evolved with the presence of various helminthic worms also have implications for our health?

A growing number of researchers think it’s likely. They posit the “Old Friends Hypothesis,” which suggests that helminthic worms and other parasites commonly assumed to be wholly pathogenic are actually “old friends” that can provide a steady, low-level anti-inflammatory buffer that reduces the incidence of autoimmune diseases like celiac, multiple sclerosis, type 1 diabetes, and Crohn’s disease. Populations with high parasite loads tend to display a remarkable absence of autoimmune disease as well as distinctive genetic markers that bias them toward higher baseline inflammation levels that are only held back by the presence of worms. Many of the alleles associated with having parasites are also associated with celiac, multiple sclerosis, colitis, diabetes, and rheumatoid arthritis, which suggests parasite/host co-evolution. In the presence of worms, maybe those alleles become harmless.

If you’re wondering why worms would ever be a “good thing,” you have to realize that helminthic worms are stubborn. They get lodged in there. They can’t really be removed by our immune system because the inflammatory response required to do so would damage the host (that’s us) more than keeping the thing around would damage the host. In turn, the worm doesn’t want to overstay its welcome by taking too much from the host and killing it. So, the host adapts to its inextricable bedfellow, while the bedfellow adapts to its host by modulating the host’s inflammatory response. And in time, it becomes reliant on the parasite, and the parasite becomes an external fixture of our immune system. It’s not really part of us, but we treat it like it is because it’s been there for so long over so many generations that we can’t function without it. We’re used to the inflammatory buffer. Humans have encountered many different species of helminth, and most, if not all of them modulate immune function in unique ways.

And when it’s no longer there, when we move to cities and stop having parasite-enriched dirt under our fingernails, when we enact widespread sanitation measures and clean up our water and throw our trash away in nice neat bins that get cleaned every week, there are unforeseen consequences. Even though infectious disease rates and deaths from infectious disease drop, and more infants make it through to adulthood, there’s no free lunch. As long as the old friends are there to buffer against the elevated inflammation, autoimmune disease is relatively absent. When the old friends are withdrawn (like through anti-helminthic therapy), autoimmune disease and allergies increase.

So, what should we do? Go spelunking in a rural Indonesian porta-potty? Take shots of Ganges River water? French kiss a pig? You’d actually be surprised. One guy cured his asthma by walking barefoot through the latrines of Cameroon. While that may be the “most Primal” way to do things, it’s not advised. As mentioned earlier, there are a lot of parasites out there whose effects we don’t quite understand and there are plenty whose effects we know to be pathogenic. Inoculating yourself with random wild helminths could cure your allergies or it could give you tapeworm (or both, I suppose).

Trials have been completed and more trials are underway, and the results are extremely promising thus far. Just so you know I’m not pulling your legs, let’s go through a few of them:

Inflammatory bowel disease (Crohn’s, colitis): Epidemiology suggests a protective effect of childhood helminth exposure on IBD risk, but what about controlled trials in adults? In one case, patients with Crohn’s disease who were exposed to hookworms had less reactivity to the parasites than controls without Crohn’s; the hookworms were less of an “immune insult,” and presumably more of an aid.

Asthma: One study found that hookworm infection mildly improved airway responsiveness in asthmatic patients, with no effect on other parameters of asthma, but the dose was small – just 10 hookworm larvae. The most common dosage for hookworm therapy is around 35 larvae, so it’s possible the dosage was just too low.

Celiac disease: Human hookworm infection suppresses the inflammatory immune response to gluten normally seen in patients with celiac. It even improves mucosal immunity and may help heal celiac patients, not just suppress their response. However, another study using an oral wheat challenge (equivalent to 16 grams of gluten a day, which is a fairly high dose) in celiacs found no benefit to hookworm infection.

Okay, that’s cool and all, but we’re still dealing with worms wriggling around in your gut. There’s little else more unnerving and repulsive than the thought of hookworms setting up shop in and gnawing on your small intestinal lining. And there are dangers to helminths, particularly in developing countries where people tend to be malnourished, absent access to medical care, and carry large parasite loads. Most intestinal worms consume blood. Get enough of them lodged in there and you can end up with anemia, malnutrition, growth deficiencies – especially if you’re a young child.

But anemia only occurs when people are getting reinfected due to frequent contact with parasite-laden fecal matter in the environment and the parasite loads get out of hand. In a controlled, clinical setting where infection is carefully curated (to prevent reinfection) and the patients have access to plenty of nutritious food and medical care, it’s far safer. As it stands now, helminths must satisify certain safety and efficacy parameters before being considered for therapy. Qualifying worms:

should not have the potential to cause disease in man at therapeutic doses

should not be able to reproduce in a host, thus allowing control of dose

should not be a potential vector for other parasites, viruses, or bacteria

should not be easily transmissible from the host to other people

should be compatible with a patient’s existing medication

should have a significant period of residence in the host

must be easily eradicated from the host, if required

The majority of clinical trials of helminthic therapy have a relative paucity of adverse reactions. Diarrhea, stomach upset, and skin irritation are the most common side effects, but usually only for the first few days and not in everyone. If it were to get out of hand, anti-parasite drugs are effective, fast-acting, and safe.

Grok definitely had parasites, but he probably wasn’t loaded to the gills, instead carrying just a few select species. The most prevalent helminth among a group like the San Bushmen, for example, is necator americanus, the human hookworm (PDF) species thought to have the most therapeutic potential. The largest parasite loads are seen in agricultural communities whose inhabitants have close, constant contact with animals (and their waste) and each other (and their waste). Hunter-gatherers had (and have) higher parasite loads than modern industrialized populations, but not as high as agriculturalists because they were steadily on the move and switched locations when parasites and parasite-laden feces became a problem. When hunter-gatherers hunker down and become sedentary, parasite infections skyrocket.

Pig whipworm is a current favorite among helminth enthusiasts, since it’s non-native to humans, it doesn’t survive for long and it doesn’t reproduce in the human host. This prevents overpopulation, but it also necessitates frequent re-dosing of eggs to maintain treatment, which gets very expensive. Treatment with pig whipworm can easily hit thousands of dollars per month.

Necator americanus, the human hookworm, appears to have the most potential against autoimmune diseases. It’s native to humans, cost-effective (lives for 3-5 years inside the host after a one-time infection), and sheds its eggs in the feces. As long as your feces are going into a toilet and not your backyard, there’s no chance of increasing your parasite load from reinfection.

This information isn’t easily actionable, not like information about exercise or diet or sleep is actionable. First of all, worms are scary. Way scarier than trying squats or eating liver or setting a strict bedtime. Parasites can be problematic, and many of us really have no way of safely inoculating ourselves. Which ones? Where do we find them? What if we mess up and get something really pathogenic? After all, the people who do carry parasite burdens generally don’t go about looking for them; they just pick them up through incidental, everyday contact. Clinical trials are underway, and I’d imagine the FDA will be getting involved soon enough.

If you are interested in helminthic therapy, you’ll probably have to handle things yourself. Here are a few ways to learn more, but please be advised that I don’t recommend, exactly, you do any of the following, and suggest you consult with a doctor before proceeding:

You could join the helminthic therapy group on Facebook and/or the Yahoo mailing list, where you’ll gain access to plenty of likeminded souls with extensive personal experience with worm therapy, as well as helpful resources, links, and advice. Brave souls are even doing some clandestine unregulated worm trading.

Also, mention it to your physician! He or she may balk or cringe or shower you with condescension, but it’s a good idea to be under medical supervision when infecting oneself with helminthic worms. And hey, if it works – and there’s a good chance it might – you very well could change an influential mind.

Is there a role for helminths in general health and immunity? Probably. But I’d wait for more research to take place before having nematode eggs and bacon for breakfast. If you’re suffering from any of the diseases shown to be modulated or improved by helminthic therapy, however, it might be worth researching.

What about you guys? Grossed out? Intrigued? About to book a trip to Cameroon? Let’s hear your reactions in the comment section!

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Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

Good luck to all you brave souls willing to jump in the latrine…

For now I am going to stick with the bacteria and fungi from my cultured food.

I have personally used hookworm to combat severe allergies and asthma. Usually you are dosed with 25 invisible hookworm larvae, placed on the skin under a bandaid. Yes they do go in through skin causing itching, but the rash is like having poison oak or ivy. Often you take another dose or two of 25 after a few months. It is really not gross – only in your mind, but the benefits can be great for some people who have not been able to relieve severe allergies by other treatment.

This article helps explain why it’s important for kids to play outside. I played outside all the time as a kid (except in the hottest part of the day in the summer), and I really don’t get sick very much.

Being outside in the woods- getting fresh air, lots of sleep and exposing yourself to (gasp) nature- is always a good thing.

Yes, probably, I wish there was a .gif instead of just a picture for this post. Something showing a parasitic worm or piece of creature latch on over and over or already comfy and plunging its blood extractor. Or rearing back dripping blood from its maws after gorging on someone’s inner skin.

This is funny in a way. You know, I can totally imagine that 30 years from now, people will be taking probiotic capsules with worm eggs in them. Taking bacteria as a supplement was surely just as gross a thought in 1950.

Parasites are not only primal, but they were pretty common in modern man up till about 150 years ago. That’s really when trash and sewage started being hauled away in cites, also coinciding with anti-helminthic drugs, and worm infestations started dropping dramatically. It was most likely unprecedented in human history.

I think worm therapy and fecal transplants are two of the most promising medical interventions currently being studied. They are probably the two grossest as well, although most medicine is pretty icky when you think about it.

The book “An Epidemic of Absence” is a great read for anyone interested in this subject.

Lastly, there may be things you can do to mimic some of the possible benefits of having a hookworm without actually hosting a hookworm. For example, if you are interested in benefits of iron reduction that worms provide, you could simply donate blood as opposed to cultivating a colony of hookworms. In “The Iron Factor of Aging,” Francesco S. Facchini suggested that low iron stores where a feature of all primal indivuals, due to blood lost in battle or other trauma, and also from worms.

It certainly varies. If your iron stores are low or you are anemic, it absolutely is not a good idea. However, Iron can become elevated, and be seriously problematic. Hemochromatosis is a serious disease, and is associated with all sorts of problems, from liver damage to diabetes to heart disease and cancer. It’s the most potent oxidant we encounter, which is great for hemoglobin, but also great at generating free radicals. Lower iron levels are the current thinking as to why women tend to suffer fewer heart attacks than men. Add to that that frequent blood donors tend to live longer and have less disease. And also, clinical trials that lowered even modestly high iron levels saw an improvements in things like glucose tolerance, insulin sensitity, and blood pressure, and I would say it’s foolish NOT to monitor your iron levels, and get them toward the lower end of the spectrum. “Exposing the Hidden Dangers of Iron” is a health book that everyone should read.

When my iron was at the low end of normal and my ferritin was very low due to the consumption of gluten I had hair loss and was getting sick with colds that lasted for much longer than usual. Avoiding gluten completely and iron supplements for 6 months, my hair is much better and no colds for a year now! Just because our ancestors might have suffered from anemia I don’t think that this is the optimal way to live and thrive.

Anemia is NOT a good. Period. But excess iron isn’t good, either. Think of insulin for a second. Injecting it can be benficial and even life saving to a diabetic. But injecting it into someone with normal levels can be deadly. Again, I believe it’s something everyone should monitor.

Having suffered from large roundworm infections at least twice, I find this hard to believe. I have come to believe that my recurrent infections were due to my leaky gut, celiac disease and dysbiosis brought on by the SAD. I am hopeful that by following a primal diet, I can heal my gut, boost my immune system and avoid recurring parasitic infections.

Coronado Biosciences bet the company on helminth therapy for Crohn’s. Clinical trials failed, however (they said that placebos had a better than expected result!) and their stock tanked. (Analysts are touting the stock after a recent rally for no apparent reason, but the “rally” is from $1.50 to about $3, after being as high as $12.50).

They’re still looking at TSO (Trichuris suis ova) therapy for autism but unfortunately the best clinical trials for TSO and Crohn’s have turned up nada.

I remember reading a Chris Kesser interview with Moises Velasquez-Manoff, who actually wrote a book on this stuff. Really interesting – I’m glad Mark is posting about this!

I’ve heard that much of helminth’s ability to modulate the immune system is also a function of timing (how old you are when you first become infected). Mark – do you know anything about timing and the efficacy of helminths?

We host more than we know already. I still shudder at close ups of eyelash mites we all have.

Intentionally ingesting parasites does sound grotesque, but so does fecal transplants, and that has proven to be a literal life saver for many conditions. So, while I am not going to jump right into this, I will definitely be following the studies in the future.

i have been using fecal transplants from my life partner every other day for 2 years, I have no colitis symptoms any longer. Yes, when we began, it seemed to so gross. It has however, redeemed my life! Well worth the ick factor.

Pinworms. Easy to diagnose- stick a piece of scotch tape to the affected area in the morning right after waking up. Take to clinic and the lab will look at it under a microscope to see the little buggers. Easy treatment too.

Lora wrote on January 24th, 2014

You might try a good cream, such as Aquaphor, before assuming you need to be dosed for worms. Might just be dry skin. Hemorrhoids can itch, even if you think you don’t have them. Also, food allergies can cause anal itching.

Well, people living in the country usually find out they have parasites at some point in their childhood lives, take some blue pills and Viola they are gone. I wonder if that’s why I am so healthy now? Well, now that I no longer eat junk food that is. Just the thought of worms gets the “ew, gross” reaction from this sissy-la-la for sure. However, don’t know if I’d consider it as one of the last resorts if I had some problem that won’t go away any other way…..

Sorry Mark- this is the only thing you’ve posted that I don’t agree with. Parasites are problematic! Hookworms cause all sorts of problems, but the biggest is that it affects people’s sleep (a good nights sleep is so important), they’re also linked with depression, anxiety, lockjaw and more. Hulda Clark claims that parasites are the cause of cancer. They also produce waste that is very acidic!!!

There’s no doubt that parasites, and worms in particular, can be problematic. However, the Hygeine and Old Friends Hypothesis is the idea that some of these parasites could impart benefits to the host as well. It’s not like all parasites and bacteria are either just “good” or “bad,” there is likely a continuum.

And worms “acidic waste” could actually be beneficial- it’s an alkaline colon the tends to promote pathogenic bacteria and colon cancer.

I think it might be worth highlighting, if you read the post carefully you’ll find that I don’t outright “recommend” helminthic therapy. I’ve simply explained the hypothesis and the evolutionary argument for it, made an attempt at summarizing some of the interesting research going on, and discussed what diseases they’re trying to treat with it. I find it pretty fascinating, but YMMV!

Okay… sitting here reading on my lunch break, had to forgo the article until I finished my organic veggie and turkey stir-fry. But have always heard that a little dirt under the fingernails would never hurt me and may even keep my immune system healthier, ie: making mudpies, building sandcastles etc. Interesting article.

Love it! I followed the Yahoo helminthic group for a while… but I will only take the plunge if I come down with an auto-immune condition, since there are risks to inoculating with worms.

Some of the participants on that group have pretty awesome success stories too.

Coronado’s Crohns trial failed. It has a few other trials running, but from my reading of hte yahoo group it sounded like hookworms had a better chance of success than pig whipworms. But there isn’t much money to be made off inoculation once every 3 to 5 years, so who wants to try to push that through the FDA’s trials. Pig whipworms require dosing every two weeks, so there is a lot of money on the table, hence the interest from Coronado…

Well that’s the most I’ve read about the potential beneficial effects of worms in our guts. Interesting stuff. I don’t think I’m going to rush out and try and get more worms inside me, but I will keep a closer eye on this subject and who knows?

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